Electric rock-drill.



No. 852,680. PATENTBD MAY 7, 190?. J. RIDDELL & G. B. PAINTER.

ELECTRIC ROCK DRILL.

APPLICATION FILED SEPT. 19, 1902. nnnnwnn 00129, 1906.

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John Riddell, George B. Painb'er; M64534 Wi nesses:

No 852,680. PATENTED MAY 7, 19074 RIDDELL & G. B. PAINTER.

ELECTRIC ROCK DRILL.

APPLICATION FILED SEPT. 19, 1.902. RENEWED 0011.29, 1906.

s SHER'I8SHEET 2v Ww nesses lnvendorq 7 John Fiiddell,

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M W m M No. 852,680. PATENTBDQ MAY 7, 1907. J. RIDDBLL & G. B. PAINTER.

ELECTRIC ROCK DRILL.

APPLIOATION FILED SEPT. 19, 1902. RENEWED 001 29, 1906.

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\A/iiinesses: 4 7, (QVW I UNITED sra rns rarer onion.

JOHN RIDDELL AND GEORGE B. PAINTER, OF SCI-IENECTADY, NEW YORK, ASSIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF. NEW

YORK.

ELECTRE ROCK DRILLE Specification of Letters Patent.

Patented May 7, 1907.

such an electric rock-drill as is set forth in the patent to George W. Pickett, No. 632,658, dated September 5, 1899, although it is applicable to any type of rock-drill in which a hammer blow is delivered upon the head of the drill.

In mechanism heretofore proposed for holding and turning the drill, the tool has been. held more or less rigidly in the clutch or head, so that if in operating the drill the feeding mechanism didnot happen to carry the drill-p'oint to the bottom of the hole, the blow delivered by the hammer on the head of the drill would be transferred to the clutch itself,

and back through it to the actuating mechanism. It is evident that a clutch or drillhead which would leave the drill perfectly free at the instant the blow was struck would relieve the apparatus from this objectionable feature, and it is the object of our invention to accomplish this result.

A further object is to enable a large drill to be readily inserted and removed from the holder.

The invention consists in a drill-head or clutch comprising jaws or dogs which automatically grip the drill and hold it firmly while it is being retracted and partially rotated but which let go the drill when it is advanced and thus leave it perfectly free to transmit the blow of the hammer to the cut-.

ting edge and the material which is being opcrate-d on. v

The invention also consists in certain details of construction hereinafter set forth.

In the accompanying drawings, Figure 1 is a side elevation of an electric rock-drill of the Pickett type equipped with our improved drill-head'; Fig. 2 is a sectional elevation of the drill-head; Fig. 3 is a cross-section thereof on the line 3 3 of Fig; 2; Fig. 4 is a cross- 1 section thereof on the line 4 4, Fig.2; Fig. 5 is a longitudinal section of the portion thereof on the line 5 5, Fig. 2; Fig. 6 is a perspective view of one of the gripping dogs; Fig. 7 isa perspective view ofthe feather which effects the turning of the drill-head; F 8 is a I sectional elevation showing the manner of removing a drill; Fig. 9 is a cross-section of Fig. 8 on the line 9 9, and-Fig. 10 is a perspective view of the spring catch for the pin on which the fork turns.

An electric rock-drill of this type consists of three general parts, viz., a drill mechanism comprising a drill supported in a suitable holder so that it can be struck a rapid series of blows by a hammer, an electric motor, and

means of which the rotation of the armature of the motor actuates the hammer and at the same time retracts and turns the drill after each blow. The general appearance of such a drill is shown in Fig. 1, in which it is arranged for drilling a hole vertically downward. It will be understood, however, that The electric motor and operating mechanism which actuate the hammer 1 are not shown, since they form no part of our invention. They are inclosed in a casing 2 which serves as the main frame of the ,machine. This casing is in turn supported by a frame or bedpiece 3 upon which it has a longitudinal movement controlled by a screw 4 at tached to the frame 3 and working in a nut 5 secured to the frame 2, so that by turning the screw by means of the crank 6 the casing 2 and with it the operating mechanism maybe will. The frame 3 is provided with a lug. or trunnion 7 and with adjustable lugs 8 so that it may be clamped to a column or fixed directly to the walls of a shaft or tunnel in any desired position in the usual way.

Secured to the casing 2 is a holder 9 through which the drill 10 passes longitudinally, the head and point of the drill projecting above and below the holder as shown. Inside the holder and concentric with the retracted and artially turned between the blows ofthe Iiammer. This clutch comprises a sleeve 11 having an easy fit on the shank of the drill and provided with a circumferential groove 12 with which engages a mechanism interposed between the two by it can be adjusted to work in any direction.

advanced or retracted by the operator at drill is a clutch by means of which the drill is v LII 4 and retracted with the sleeve 11.

fork 13 connected by a rod 14 with a tailpiece 15 constituting a part of theactuating mechanism, as fully set forth in the Pickett patent above referred to. The fork 13 is pivoted at its rear end on a pin 16 so that the longitudinal reciprocation of the rod 14 will oscillate the fork up and down and therebylift and lower the sleeve 11.

In order that the lifting movement of the sleeve may be communicated to thedrill, we provide a plurality of dogs 17'arranged radially around the drill in an enlarged portion 11 of the sleeve and capable of movement lengthwise of the sleeve. The dogs are guided and held in their relative positions by means of radial slots 18 in the lower end of ,the enlargement 1 1. The under side of each dog has a V-sha ed notch forming teeth 17 17 having inc ined surfaces. The upper end of the sleeve 11 is conically countersunk to engage with the inner teeth 17'. That portion of the head adjacent to the conical upper portion of the sleeve is beveled to enter. said notches also, and engage with the outer teeth 17 as clearly shown in Fig. 2.

We prefer to provide means for exerting a downward pressure on the dogs in order to insure their biting the drill. This may consist of one or more blocks of rubber 19 placed above said dogs, either with or without an interposed washer 20, and restrained from upward movement by means of a cap 21 suitably secured to the upper end of the enlargement 11, as by means of the pins 22 and the bayonet-joint notches 23.

The partial rotation of the sleeve between the blows of the hammer is effected by means of a stationary feather 24 adapted to slide longitudinally and rotate in a socket 25 projecting from the holder 9 and-urged yieldingly inward by a spring 26. The feather enters a zigzag groove in the outer surface of the sleeve 11. nate longitudinal grooves 27 and helical grooves 28, the former intercepting the latter at points not far from their upper ends and the latter intercepting the former at points not far from their lower ends, as clearly shown in Figs. 2 and 8. Each groove is deeper at its outer end and slopes gradually upward to its other end where it intersects the other groove, as clearly shown in Fig. 5. The result is that at the points of intersection there is a slight shoulder 29..

The operation of the device is as follows:

When the sleeve 1 1 is retracted by the fork- 13 its u per end lifts the dogs 17* away from the beve ed stationary surface of the holder 9 and by reason of its conical inner surface acting on the inner teeth 17 draws the dogs tightly against the drill which is thus firmly clutched This action is facilitated by the pressure of the rubber 19 on the upper ends of the dogs, which tends to force them into the sleeve and Said groove comprises alter-,

against the drill. During this upward move ment of the sleeve the feather 24 is in engagement with one of the helical grooves 28, and as the sleeve rises past the stationary feather it is given a partial rotation until the feather drops over into the next longitud nal groove 27, after which the upward travel of the sleeve is without angular movement. \Vhen the sleeve descends the feather is in engagement with the longitudinal groove and is prevented from reentering the helical groove in which it formerly lay by reason of the shoulder 29 at the junction of said two grooves. The sleeve is therefore caused to descend without any angular movement 11I1t1l,'8 S it approaches its lowest point of movement, the feather drops into the nexthelical portion of the groove and the sleeve is thus given a slight retro ade angular movement as it reaches the ower end of its travel. Just before the sleeve comes to rest, the outer teeth 17 of the dogs slide down upon the stationary beveled portion 30 of the holder, the dogs being thereby vwithdrawn from the drill, which is thus leftentirely free in the clutch so that the blow of the hammer will not be imparted to any portion of the mechanism.

A valuable feature of our invention is the facility with which the drill can be changed. In order to eifect this, the pin 16 is drawn out, as shownin Fig. 9, being quickly released by disengaging the spring-arm 31 from the groove 32 in said pin. A second groove 33, with which said arm engages, holds the pin in the position shown in Fig. 9, so that it will not be lost. The fork 13 is disengaged from the groove 12 in the sleeve and dropped into an upright position, as shown in Fig. 8. The feather 24 is drawn back out of engagement with the groove in the sleeve, .and is locked in this position, preferably by giving it a uarter turn, so thatthe transverse pin '34 wi I be caught on the projection 35 on the cap 36. The cap 21 is then loosened to re lieve the pressure of the spring 19 onthe dogs, and relax their grip on the drill. This leaves the sleeve free to be lifted out of the holder, as shown in Fig. 8. The drill can then be easily drawn up through the holder 9. By making the shanks of the drills of substan tially uniform size, so that the same set of dogs can be used, the cutting points may be made of any size capable ofpassing'through the holder. This is of especial usefulness in drilling deep holes, which are begun with a large drill, but at certain depths are continued with smaller and smaller drills; With our device, the drills can be readily and uickly changed without disturbing the mac e.

What We claim as new and desire to secure by Letters Patent of the United States, is,--

1. An electric rock-drill provided with means for; clutching the drill, means for re- IIO tract-ing and turning and also advancing it,

esaeso and means for unclutching it when advanced, so that it will be entirely free when struck.

2. In a rock-drill, a'reciprocating clutch provided with dogs, and means for causing said dogs to bite the drill when the clutch is retracted, and means for causing said dogs to let go when the drill has been advanced and prior to being struck.

3. In a rock-drill, a reciprocating clutch provided with radially movable dogs, and means for moving said dogs inward when the clutch is retracted and means for moving them outward when the clutch has been advanced and prior to the drill being struck.

4. In a rock-drill, a plurality of radially movable dogs, each having oppositely in clined surfaces, a relatively movable sleeve having an inclined surface adapted toco-operate with the surfaces of the dogs inclined n one direction, and a stationary holder for said sleeve having a beveled portion to engage the opposite inclined surfaces on the do s.

In a rock-drill, a sleeve having a conically countersunk upper end, a cupped enlargement on said sleeve having radial slots, dogs fitted to move radially and longitudinally in said slots and provided with V- shaped notches engaging the end of the sleeve, and means for pressing said dogs into said sleeve.

6. In a rock-drill, a sleeve having a conically countersunk upper end, a cupped enlargement on said sleeve having radial slots, dogs fitted to move radially and longitudinally in said slots, and provided with inclined surfaces enga in the sleeve, and one or more rubber bIocks resting on said dogs.

7. In a rock-drill, a sleeve having a conically countersunk u per end, a cupped enlargement on said sfeeve having radial slots, dogs fitted to move radially and longitudinally in said slots, and rovided with inclined surfaces engaging the s eeve, one or more rubber blocks restingon said dogs, and a cap secured to said enlargement and confining said blocks.

8. In a rock-drill, a reciprocating sleeve provided with alternate longitudinal and helical grooves intersecting one another at points near their ends, said grooves being deeper atone end than at the other, and a spring-pressed feather engaging with said grooves.

9. In a rock-drill, a reciprocating sleeve provided with alternate longitudinal and helical grooves intersecting one another at points near their ends, said grooves being deeper at one end than at the other, and one deeper than the other at the oint of intersection, and a spring-pressed eather engaging said grooves.

10. In a rock-drill, the combination with a holder, of a sleeve-clutch having a circumferential groove, a fork engaging with said groove, a pin on which said fork is pivoted, having grooves at two points, and a springarm to enter said grooves and lock the pin both when in place and when withdrawn from the fork.

'JoHN RIDDELL.

GEORGE B. PAINTER.

Witnesses:

G. C. HoLLrsrER, I'IELEN ORFORD. 

